The disclosed subject matter relates to techniques for coupling light into graphene.
Graphene, which can be configured from a single atomic layer of graphite, can possess certain electronic properties that can be utilized in certain optoelectronic devices, such as photodetectors, tunable broadband modulators, saturable absorbers, and nonlinear media for four-wave mixing. Although the optical absorption of graphene can be considered high given its single atom thickness, it can be relatively low in absolute terms, for example with an absorbance of approximately 2.3% in the near-infrared and visible. A stronger absorption can be useful for many electro-optic and all-optical applications. The absorption, and generally the light-graphene interaction, can be increased using a variety of techniques, including surface plasmon polariton states, which can provide sub-wavelength confinement, guided modes in silicon waveguides, which can allow for 3 dB optical attenuation over a 40 μm channel length, and distributed Bragg reflector microcavities, which can enhance light absorption on the order of 26 times on the resonant wavelength. However, in certain applications where a strong light-matter interaction is desired, further increases in the interaction length of light with graphene is desired. Accordingly, there remains a need for improved techniques for coupling light into graphene.